Pneumatic-action for musical instruments.



No. 794,911. PATENTED JULY 18, 1905.

F; W. WOOD.

PNEUMATIC AdTIONIOR MUSICAL INSTRUMENTS. APPLICATION FILED MAR.31,1905.

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UNITED STATES latented July 18, 1905.

PATENT OFFICE.

PNEUMATIC-ACTION FOR MUSICAL INSTRUMENTS.

SPECIFICATION forming part of Letters Patent No. 794,911, dated July 18, 1905.

Application filed March 31,1905. Serial No. 253,202.

To all whom it may concern.-

Be it known that I, FnEDERIcn W. W001), a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Pneumatic-Actions for Musical Instruments, of which the following is a specification.

This invention relates to pneumatic-ac tions for musical instruments, and has for its object to produce a valve mechanism which will adapt itself to its seats without regard to whether the seats are disposed exactly at right angles to the valves or not.

A further object is to produce a valve construction which does not require the valveopening to be of larger size than usual, and yet permits of the passage of the necessary volume of air to effect the instantaneous ac tion of the pneumatics.

To these ends the invention consists in certain novel and. peculiar features of construction and organization, as hereinafter described and claimed, and in order that it may be fully understood reference is to be had to the accompanying drawings, in which-- Figure 1 represents a vertical transverse section of the pneumatic action, the section being taken mainly in the plane of line I I of Fig. 2. Fig. 2 is a section on the line II II of Fig. 1. Fig. 3 is an enlarged vertical section similar to the upper part of Fig. 1, but showing the lower valve-seat distorted or at an angle to the upper one. Fig. 4 is a vertical section showing the type of valve in common use, said figure showing the stem thrown out of plumb slightly.

Referring now to the drawings, where like reference characters identify corresponding parts, 1 indicates the exhaust-chamber of the pnuematic-action mechanism, the same exhausting into the equalizer (not shown) and then to the pumps, also not shown, because these parts are of common and well-known construction and have nothing to do with the present invention. A pneumatic 2 for each tracker-bar opening, the tracker-bar being also omitted because forming no part of this invention, is secured to the under side of the bottom of the exhaust-chamber and is adapted to be connected in the usual or any preferred manner to operate the musical instrumentfor instance, a piano-and for each pneumatic there are a passage 3 and a valvechamber 4, each valve-chamber opening into the eXhaust-chamber through its opening 5 and to the atmosphere through its opening 6,

said openings being bridged at their lower and I upper sides, respectively, by guide-bars 7 for the valve-stems 8, each stem resting at its lower end on a block 9, secured to the flexible diaphragm 10. This diaphragm may be of leather or rubber, preferably the latter, because there is less danger of leakage of air through it and may extend the full length of the exhaust-chamber and bridge cavities -11 in the bottom thereof equal in number to the valves, or there may bea' diaphragm for each valve, the diaphragm bridging the cavity or recess 1 1 in the upper side of a block 12, se cured on the bottom of the exhaust-chamber. In order to prevent noise when a block 9 strikes the bottom of a cavity 11, each block 12 is provided with a cushion 13.

14 is a passage for each valve below the exhaust-chamber, one end opening into cavity 11 directly, as shown in Fig. 3, or into said cavity through an aperture 15 in block 12 and cushion 13, as shown in Fig. 1. At its opposite end each passage 14 is provided with a connecting-tube 16, leading to the tracker-bar in the usual manner, and said passage is provided with a fine partitioningscreen 17 to exclude from the valve mechanism any small foreign particles which may be drawn into the tracker-bar, and connecting each passage 14 with the exhaust-chamber between the screen and diaphragm is a vent passage 18.

A valve for alternately closing and uncovering the alined openings 5 and 6 consists of two similar members, each comprising the frustum-shaped body portion 19, fitting loosely on stem 8, and the outer portion or flange 2Q projecting from the base of the frustum-shaped portion, the lower member being upright and the upper member inverted, so that their apices may bear against the inter osed washer or washers 21, mounted to sli e upon and have a substantially air tight relation with the stem, a collar or shoulder 22, rigidly secured to orformed with the stem within the frustum-shaped body of the lower member, serving to lift said members when the stem rises. To make the joint noiseless and air-tight between the flange of the lower member and the'bottom of the valve-chamber, a cushion 23 is provided, the same being preferably secured to the bottom of the chamber, and to make the joint between the flange of the upper member and the top of said chamber air-tight said upper member is provided with a cushion 24.

In order to prevent the hissing sound attendant upon a rush of air past a hard surface, the top of the valve-chamber is also lined with leather or its equivalent, as at 25.

As well known, when the machine is in operation air is being continuously exhausted fromv chamber 1 through the equalizer and pumps, so that said chamber is practically a vacuum-chamber. l/Vhen the tracker-lair opening communicating with a tube 16 is closed by a nonperforated portion of the note-sheet, diaphragm 10 is depressed, and the valve is closing opening 5 and uncovering opening 6 to admit air therethrough and through chamber 4 and passage 3 to the pneumatic 2, which is therefore inflated, it being understood that the vent-passage 18 permits the air below diaphragm 10 to be like wise exhausted into and from the vacuumchamber, as otherwise the diaphragm could not be depressed.

Now when a perforation in the note-sheet or roll of paper registers with the tracker-bar opening referred to, air enters the trackerbar and because the cavity 11 is of greater area than the surface of the valve raises the diaphragm and its valve, and thereby uncovers opening 5 and covers opening 6, this result being instantly followed by the ex- .haustion of air from and consequent collapse of the pneumatic, the collapse of the )neumatic resulting in the operation, of the musical instrumentviz., in the operation of a key of the piano and in the consequent production of sound-it being understood in this connection that the vent-passage is so small that the small quantity of air which passes through it into the exhaust-chamber offers no material resistance to the upward movement of the diaphragm. As the progress of the note-sheet again results in closing the tracker-bar opening the parts resume their original positions and the weight of the mechanism. between the pneumatic and the piano, added to-the gravitative tendency of the former and the rush of air therein, effects the instant reexpansion of the pneumatic. All subsequent ormrations are repetitions of those described.

It will be seen that as the air rushes into the pneumatic when the parts are disposed as shown the cushioned surfaces 24 and 25 prevent any hissing sound and that the vari ous cushions deaden or prevent any sound which would naturally follow the impact of the valve or other part against the arresting surfaces, this being true on both the upwardand downward movement.

In view of the fact that the valve members are loosely mounted on the stem it is obvious that any slight distortion of the parts, such as shown in Figs. 3 and 4, due to warpage or imperfect assemblage of the parts, does not result in an imperfect seating of the valves, because the valve members are free to assume different angles to the axis of the stem, and thus bear snugly against their respective seats, the angular position of either member not resulting in the passage of air through the opening in its apex, because of the closelylitting washer or washers 21, which washer or washers, because of compressible n'iaterial, yield to permit such angular relation of the valve members.

, It will also be noticed that the hollow conical form of the lower member permits the collar which elevates the valve with the stem to occupy a position above the flange of the lower member, and therefore does not at any time obstruct the passageo'f air through opening 5, whereas with the type of valve shown in Fig. 4 said collar is never wholly withdrawn from opening 5 and by occupying the same obstructs the passage of air to some extent, the result being a slower collapse of the pneumatic than would otherwise occur.

The peculiar type of valve shown by me furthermore provides a more OXlZOIHlOd hearing surface or area than that shown by Fig. 4 and in addition concentrates the air against the center of the valve, and thereby more efficiently and reliably operates the same, it be ing noticed in this connection that dispensed with the use of a collar on the valve stem above the upper member, as the same has been found superfluous in practice.

From the above description it will be apparent that I have produced a pneumatic action for musical instruments which embodies the features of advantage emunerated as desirable in the statement of invention and which obviously is susceptible of modification in some particulars without departing from the principle of construction involved.

Having thus described the invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a pneumatie-aetion. for musical instruments, a valve-chamber having alined openings, :1. reciprocatm'y valve-stem extending through said openings and suitably guided, valve n'lembers mounted loosely on said stem, one to control one of the valveopenings and the other the other valve-oprming, a compressible washer or washers fitting slidingl'y and with a substantially air-tight ITS relation on said stem between said members, and means rigid with the valve-stem for moving said valves simultaneously to uncover one valve-opening and cover the other.

2. In a pneumatic-action for musical instruments, a valve-chamber having alined openings, a reciprocatory valve-stem extending through said openings and suitably guided, valve members mounted loosely on said stem, one to control one of the valveopenings and the other the other valve-opening, and comprising substantially frustumshaped portions inverted with respect to each other, a compressible washer or washers fitting slidingly and with a substantially airtight relation on said stem between said members, and means rigid with the valvestem for moving said valves to uncover one valve-opening and cover the other.

3. In a pneumatic-action for musical instruments, a valve-chamber having alined openings, a reciprocatory valve-stem extending through said openings and suitably guided, valve members mounted loosely on said stem, one to control one of the valveopenings and the other the other valve-opening, and comprising substantially frustumshaped portions inverted with respect to each other, a compressible washer or washers fitting slidingly and with a substantially air,- tight relation 011 said stem between said members, and a collar or shoulder rigid with l said valve-stem and occupying the hollow of the frustum-shaped body portion of one of said valves so that when the stem is moved in the proper direction, said collar shall unseat said valve member and seat the other valve member.

4. In a pneumatic-action for musical instruments, a valve-chamber having alined openings, an upright reciprocatory valvestem extending through said openings and suitably guided, valve members mounted loosely on said stem, one to control the lower valve-opening and the other the upper valveopening, and each comprising a frustumshaped body portion and an outwardly-projecting flange at the base of said body por tion, the frustum-shaped body portion of the lower member projecting upwardly and that of the upper member downwardly, and a collar or shoulder rigid with said valvestem and occupying the hollow of the frustum-shaped body portion of the lower member of said valve so that when the stem is moved upward said collar shall unseat the lower member and seat the upper member.

In testimony whereof I affix my signature in the presence of two witnesses.

FREDERIOH W. WOOD.

Witnesses:

H. 0. RODGERS, G. Y. THORPE. 

